collator for grpo and prompt loader

src/axolotl/core/trainer_builder.py

@@ -797,6 +797,9 @@ class HFCausalTrainerBuilder(TrainerBuilderBase):
     def build_collator(
         self, training_args: AxolotlTrainingArguments, is_eval=False, **kwargs
     ):
+        if self.cfg.rl == "grpo":
+            return GRPOStrategy.get_collator(self.cfg, training_args, **kwargs)
+
         if training_args.pretraining:
             if self.cfg.pretraining_sample_concatenation is False:
                 return DataCollatorForSeq2Seq(self.tokenizer, **kwargs)

src/axolotl/core/trainers/grpo/__init__.py

@@ -50,3 +50,12 @@ class GRPOStrategy:
             trainer_kwargs["reward_funcs"] = reward_funcs
 
         return trainer_kwargs
+
+    @classmethod
+    def get_collator(
+        cls, cfg, training_args, **kwargs
+    ):  # pylint: disable=unused-argument
+        def data_collator(features):  # No data collation is needed in GRPO
+            return features
+
+        return data_collator

src/axolotl/prompt_strategies/base.py

@@ -13,18 +13,19 @@ def load(strategy, cfg, module_base=None, **kwargs):
         if len(strategy.split(".")) == 1:
             strategy = strategy + ".default"
         load_fn = strategy.split(".")[-1]
-        strategy = ".".join(strategy.split(".")[:-1])
         if len(strategy.split(".")) > 1:
             try:
                 importlib.import_module(
-                    "." + strategy.split(".")[-1],
-                    ".".join(strategy.split(".")[:-1]),
+                    strategy.split(".")[-2],
+                    ".".join(strategy.split(".")[:-2]),
                 )
-                module_base = ".".join(strategy.split(".")[:-1])
-                strategy = strategy.split(".")[-1]
+                module_base = ".".join(strategy.split(".")[:-2])
+                strategy = strategy.split(".")[-2]
             except ModuleNotFoundError:
                 pass
-        mod = importlib.import_module(f".{strategy}", module_base)
+        else:
+            strategy = "." + ".".join(strategy.split(".")[:-1])
+        mod = importlib.import_module(strategy, module_base)
         func = getattr(mod, load_fn)
         return func(cfg, **kwargs)
     except Exception:  # pylint: disable=broad-exception-caught